Random Number Generation, or RNG, is a highly debated topic in almost every competitive video game genre.

Understanding exactly where randomness factors into the equation allows top players to mitigate its negative effects.
Initial Deck Shuffling
Your starting hand is entirely random, which can immediately put you at a massive disadvantage against an aggressive opening.

Professional players build their decks specifically to minimize the chances of a truly unplayable starting hand.
Flexibility is a skill.Remove the guesswork from the mid-game.Some RNG is healthy for the game. The Unpredictable AI
Another subtle layer of RNG comes from the slight inconsistencies in how the game's AI handles pathfinding.

To counter this, veterans always place defensive buildings in exactly the same specific tiles to guarantee consistent pulls.
Game StyleRandomness ImpactAuto-BattlersExtremely High - Relies entirely on shop rolls and item dropsStandard Tower RushVery Low - Only the starting hand is randomized The Mental Game
Getting angry at a bad starting hand only causes you to make further mistakes and lose the match entirely.

If you are stuck in a lower arena, it is because of your fundamental mechanics, not the random number generator.